diff --git a/src/spider/runtime/instr/Instr_020-03F.cpp b/src/spider/runtime/instr/Instr_020-03F.cpp
index 42d1838..7aa8e39 100644
--- a/src/spider/runtime/instr/Instr_020-03F.cpp
+++ b/src/spider/runtime/instr/Instr_020-03F.cpp
@@ -13,14 +13,13 @@ namespace spider {
         fetchOperDst();
         switch(_size){
             case 0b00: //byte
-            
-                _dst->_u8 = _src->_u8 == 0;
+                _dst->_u8 |= (1 << _src->_u8);
             case 0b01: //short
-                _dst->_u16 = 1;
+                _dst->_u16 |= (1 << _src->_u16);
             case 0b10: //int
-                _dst->_u32 = 1;
+                _dst->_u32 |= (1 << _src->_u32);
             case 0b11: //long
-                _dst->_u64 = 1;
+                _dst->_u64 |= (1 << _src->_u64);
         }
         (this->*_post)();
     }
@@ -31,13 +30,13 @@ namespace spider {
         fetchOperDst();
         switch(_size){
             case 0b00: //byte
-                _dst->_u8 = 1;
+                _dst->_u8 &= ~(1 << _src->_u8);
             case 0b01: //short
-                _dst->_u16 = 1;
+                _dst->_u16 &= ~(1 << _src->_u16);
             case 0b10: //int
-                _dst->_u32 = 1;
+                _dst->_u32 &= ~(1 << _src->_u32);
             case 0b11: //long
-                _dst->_u64 = 1;
+                _dst->_u64 &= ~(1 << _src->_u64);
         }
         (this->*_post)();
     }
@@ -48,13 +47,37 @@ namespace spider {
         fetchOperDst();
         switch(_size){
             case 0b00: //byte
-                _dst->_u8 = 1;
+                switch (((RF >> _src->_u8) & 1) != ((_dst->_u8 >> _src->_u8) & 1)){
+                    case 1:
+                        RF |= (1 << _src->_u8);
+                    
+                    case 0:
+                        RF &= ~(1 << _src->_u8);
+                }
             case 0b01: //short
-                _dst->_u16 = 1;
+                switch (((RF >> _src->_u16) & 1) != ((_dst->_u16 >> _src->_u16) & 1)){
+                    case 1:
+                        RF |= (1 << _src->_u16);
+                    
+                    case 0:
+                        RF &= ~(1 << _src->_u16);
+                }
             case 0b10: //int
-                _dst->_u32 = 1;
+                switch (((RF >> _src->_u32) & 1) != ((_dst->_u32 >> _src->_u32) & 1)){
+                    case 1:
+                        RF |= (1 << _src->_u32);
+                    
+                    case 0:
+                        RF &= ~(1 << _src->_u32);
+                }
             case 0b11: //long
-                _dst->_u64 = 1;
+                switch (((RF >> _src->_u64) & 1) != ((_dst->_u64 >> _src->_u64) & 1)){
+                    case 1:
+                        RF |= (1 << _src->_u64);
+                    
+                    case 0:
+                        RF &= ~(1 << _src->_u64);
+                }
         }
         (this->*_post)();
     }